// get route name
$routeName = $app->router->getMatchedRoute()->getName();
// get group name <- work , but I do not like getPaths()
$groupName = $app->router->getMatchedRoute()->getGroup()->getPaths();
//but getRoutes() NOT WORK.
$groupName = $app->router->getMatchedRoute()->getGroup()->getRoutes();

I implement something that helps to group routes, and so to separate code into different files and folders.